I/O (アイオー) April 26th, 2032 A.D. - Megalopolis Tokyo - 00:12 in the morning .A total lunar eclipse occurs for the first time in 3 years. Even though it's supposed to be a simple astronomical phenomenon, it soon sets off a series of unexpected events. Unexplainable mysteries, terrorist incidents, and network crime surge as if in unison. The truth mixes with lies, as if the world is awake but still sleeping. Something has begun. Somewhere no one can see. Something no one knows about. This is a story of the chance meeting and tragic parting of the young men and women living in this world. Players get to play the game from 4 different points of view: